What files would I need to edit to make a new onhit property for a wepon?

EDIT: Would it be possible to make a script to change the texture of an object when fired?

you just go into the item editor and select on hit properties..... should see it in the KOTOR tool....

No. I mean like a custome one. Not a onhit property already made.

Not sure about the custom onhit properties, but if I had to guess, than no, not possible. Someone else confirm?

As to changing the texture of an object when fired, I'll say your best bet is to make two identical objects, one with the old texture and one with the new one. The script simply swaps the items when fired.

- Star Admiral

If i cant do one then i dont need to do the other.

Well SithSpecter is doing it. Try this http://www.lucasforums.com/showthread.php?t=187137)
In his Ultimate Ranged Mod, he's adding all these new ammunition types and stuff.

That isnt an on hit property. Thats an ammo type.

but he made a grenade launcher that explodes on impact in there somewhere.

Well then mabey he knows. Hopfuly he'll speak.